TREM2 and central nervous system cancer: The results for glioma, gastric cancer, renal cancer, and liver cancer were similar to those of previous research (14, 15, 24, 25); however, Tang et al. (11) showed that TREM2 expression was decreased in hepatoma cells and most human HCC tissues, which contradicts our current results, possibly because more of the samples analyzed in our study were derived from tumors in situ, rather than metastases.